I have never used any silicone on a valve cover gasket honestly to prevent leaks

Now if you want to use a adhesive in a few spots to keep the gaskets in place on the factory valve covers that’s an option

Anyways

Fel Pro 1612 is a rubber coated fiber - They work extremely good , and I only hand tighten using a nut driver

Let them heat cycle a few times - Again hand tighten with a nut driver

They work and seal very well



Fel Pro VS 50145 is also a fiber , but man is it a rock hard material , I couldn’t get them to seal properly , I could see the high torque value with these gaskets as Mopar Mitch suggested just based on the hardness of the material if you read his post


Superformance carbon x valve cover gaskets work very well also


Some purists might not like any of these gaskets I mentioned on factory stock valve covers because none of these gaskets have the tabs

Just my opinion on all these gaskets I have tested on factory valve covers